dirname/dirname.c

   1 /*      $NetBSD: dirname.c,v 1.7 1997/10/18 13:21:41 lukem Exp $        */
   2
   3 /*-
   4  * Copyright (c) 1991, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <sys/cdefs.h>
  37 #ifndef lint
  38 __COPYRIGHT("@(#) Copyright (c) 1991, 1993, 1994\n\
  39         The Regents of the University of California.  All rights reserved.\n");
  40 #endif /* not lint */
  41
  42 #ifndef lint
  43 #if 0
  44 static char sccsid[] = "@(#)dirname.c   8.4 (Berkeley) 5/4/95";
  45 #endif
  46 __RCSID("$NetBSD: dirname.c,v 1.7 1997/10/18 13:21:41 lukem Exp $");
  47 #endif /* not lint */
  48
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <locale.h>
  52 #include <unistd.h>
  53
  54 int     main __P((int, char **));
  55 static void usage __P((void));
  56
  57 int
  58 main(argc, argv)
  59         int argc;
  60         char **argv;
  61 {
  62         register char *p;
  63         int ch;
  64
  65         setlocale(LC_ALL, "");
  66
  67         while ((ch = getopt(argc, argv, "")) != -1)
  68                 switch(ch) {
  69                 case '?':
  70                 default:
  71                         usage();
  72                 }
  73         argc -= optind;
  74         argv += optind;
  75
  76         if (argc != 1)
  77                 usage();
  78
  79         /*
  80          * (1) If string is //, skip steps (2) through (5).
  81          * (2) If string consists entirely of slash characters, string
  82          *     shall be set to a single slash character.  In this case,
  83          *     skip steps (3) through (8).
  84          */
  85         for (p = *argv;; ++p) {
  86                 if (!*p) {
  87                         if (p > *argv)
  88                                 (void)printf("/\n");
  89                         else
  90                                 (void)printf(".\n");
  91                         exit(0);
  92                 }
  93                 if (*p != '/')
  94                         break;
  95         }
  96
  97         /*
  98          * (3) If there are any trailing slash characters in string, they
  99          *     shall be removed.
 100          */
 101         for (; *p; ++p);
 102         while (*--p == '/')
 103                 continue;
 104         *++p = '\0';
 105
 106         /*
 107          * (4) If there are no slash characters remaining in string,
 108          *     string shall be set to a single period character.  In this
 109          *     case skip steps (5) through (8).
 110          *
 111          * (5) If there are any trailing nonslash characters in string,
 112          *     they shall be removed.
 113          */
 114         while (--p >= *argv)
 115                 if (*p == '/')
 116                         break;
 117         ++p;
 118         if (p == *argv) {
 119                 (void)printf(".\n");
 120                 exit(0);
 121         }
 122
 123         /*
 124          * (6) If the remaining string is //, it is implementation defined
 125          *     whether steps (7) and (8) are skipped or processed.
 126          *
 127          * This case has already been handled, as part of steps (1) and (2).
 128          */
 129
 130         /*
 131          * (7) If there are any trailing slash characters in string, they
 132          *     shall be removed.
 133          */
 134         while (--p >= *argv)
 135                 if (*p != '/')
 136                         break;
 137         ++p;
 138
 139         /*
 140          * (8) If the remaining string is empty, string shall be set to
 141          *     a single slash character.
 142          */
 143         *p = '\0';
 144         (void)printf("%s\n", p == *argv ? "/" : *argv);
 145         exit(0);
 146 }
 147
 148 static void
 149 usage()
 150 {
 151
 152         (void)fprintf(stderr, "usage: dirname path\n");
 153         exit(1);
 154 }
 155